ABSTRACT

Gene therapy is the delivery of genetic material into cells for the purpose of altering cellular function. This seemingly straightforward definition encompasses a variety of situations that can at times seem unrelated. The delivered genetic material can be composed of deoxyribonucleic acid (DNA) or RNA, or even involve proteins in some cases. The alteration in cellular function can be an increase or decrease in the amount of a native protein that is produced, or the production of a protein that is foreign. The delivery of the genetic material can occur directly, as is the case with microinjection, or involve carriers that interact with cell membranes or membrane-bound proteins as a part of cellular entry. Polynucleotides can be single or double stranded, and can code for a message, or not (as is the case for antisense gene delivery). Even the location of cells at the time of gene delivery is not restricted. Cells can be part of a living organism, can exist as a culture on a plate, or can be removed from an organism, transfected, and replaced into the same or a different organism at a later time.